So I'm in India and Alum (popularly known as Phitkari here) is easily and cheaply available here. The only issue is, they're really ugly and irregularly shaped. I was wondering if anyone would know how to sort of round them out or grow them in an acceptably smoother form?

The reason I ask is because I want to popularize these as a cheap and extremely effective deodorant (been using for the last two years and it works beautifully for me, I've had huge BO issues). I cannot obviously give away ugly sharp stones as gifts or use them in handcrafted spa baskets.

I've tried growing them by immersing a single crystal in an extremely saturated solution but they've resulted in really sharp crystalline forms and I cannot for the life of me figure out how to grow them into an acceptable shape.